Patients with abnormal CT results undergo a diagnostic CT scan (in the absence of prior studies). Patients with indeterminate nodules (less than 5 mm in size) undergo surveillance CT studies within 3-4 months. If nodules remain unchanged in size, patients undergo additional surveillance CT studies at 6 months and 1 year. Patients with lung parenchymal abnormalities on CT suspicious for malignancy undergo a bronchoscopy with biopsy and bronchoalveolar lavage (BAL). Patients with abnormal CT scan(s) and negative BAL for p53 and/or K-ras mutations or normal histology and positive BAL for K-ras and/or p53 mutations undergo additional CT scans at 6 months and 1 year. Patients with biopsy-proven malignancy after bronchoscopy are referred for definitive treatment.